- Efficient Enzymatic Preparation of Flavor Esters in Water
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A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents.
- Perdomo, Igor Chiarelli,Gianolio, Stefania,Pinto, Andrea,Romano, Diego,Contente, Martina Letizia,Paradisi, Francesca,Molinari, Francesco
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p. 6517 - 6522
(2019/06/20)
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- Method for preparing formate-type compound
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The invention discloses a method for preparing a formate-type compound. The method comprises the following steps of: adopting an alcohol-type compound and 1,3-dihydroxyacetone as reaction raw materials, and under the existence of a composite catalyst and an oxidant, reacting for 2-48 hours in a reaction medium in a reactor at a reaction temperature of 25-100 DEG C so as to obtain the formate-typecompound. The method disclosed by the invention is simple, and is mild in reaction condition, and by the method, a target product can be obtained by low cost and high yield; the used catalyst has highcatalytic activity, and is easily separated from a reaction system to be repeatedly used; the whole process is environment-friendly, and the reaction raw material (1,3-dihydroxyacetone) is easily converted from a side product (glycerol) of biodiesel, so that the utilization of the glycerol is promoted.
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Paragraph 0039; 0047; 0048
(2018/07/30)
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- Method of using swelling-able acidic poly(ionic liquid) to catalyze esterification between formic acid and alkenes to prepare formate
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The invention discloses a method of using swelling-able acidic poly(ionic liquid) to catalyze esterification between formic acid and alkenes to prepare formate. According to the method, an acidic poly(ionic liquid) that can swell in formic acid is synthesized at first; 1-vinyl-3-alkyl imidazolium bromine salt ionic liquid and sodium acrylate are taken as the copolymerization monomers, and throughfree radical polymerization and acidification that uses an acid with an equal molar weight, the poly(ionic liquid) is prepared. The poly(ionic liquid) is taken as a catalyst to catalyze the esterification reactions between formic acid and alkenes; the catalytic activity of the poly(ionic liquid) is equal to that of a homogeneous catalyst and the selectivity is higher than that of a homogeneous catalyst or a heterogeneous catalyst. The swelling-able acidic poly(ionic liquid) is used to catalyze the esterification reactions between formic acid and alkenes, the characteristic that the poly(ionicliquid) can swell in formic acid is utilized, the poly(ionic liquid) is fully dispersed in the substrate, at the same time, the active centers of the acid are immobilized on the poly(ionic liquid), thus the active centers can fully contact with the substrate, and the catalytic efficiency is largely improved.
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Paragraph 0029; 0030; 0031; 0033; 0034; 0042; 0043-0046
(2018/11/04)
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- Deep eutectic solvent choline chloride·2CrCl3·6H2O: An efficient catalyst for esterification of formic and acetic acid at room temperature
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A highly efficient and selective method for esterification of formic and acetic acid with alcohols has been achieved at room temperature, with the choline chloride (ChCl)/chromium(iii) chloride hexahydrate (CrCl3·6H2O) deep eutectic solvent as a catalyst. High yields and good selectivities of organic esters are obtained using DES [ChCl][CrCl3·6H2O]2 with the molar ratio 5:1 (carboxylic acids:alcohols) at room temperature in 24 h. The ease of recovery and reusability of DES with high catalytic activity makes this method efficient and practical.
- Cao, Jin,Qi, Bin,Liu, Jun,Shang, Yuhan,Liu, Huiwen,Wang, Wenjing,Lv, Jia,Chen, Zhiyan,Zhang, Haibo,Zhou, Xiaohai
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p. 21612 - 21616
(2016/03/08)
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- Room-temperature selective aliphatic carbon-carbon bond activation and functionalization of ethers by rhodium(II) porphyrin
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Selective aliphatic carbon(α)-carbon(β) bond activation of ethers by (5,10,15,20-tetramesitylporphyrinato)rhodium(II) (Rh(tmp) (1)) was achieved at room temperature to yield corresponding rhodium porphyrin alkyls and the functionalized esters. Rh(tmp)OH was the proposed intermediate responsible for cleaving the C(α)-C(β) bond. The reaction is general for both straight- and branch-chain ethers.
- Lee, Siu Yin,Lai, Tsz Ho,Choi, Kwong Shing,Chan, Kin Shing
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scheme or table
p. 3691 - 3693
(2011/09/20)
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- Oxidative C-C bond cleavage of primary alcohols and vicinal diols catalyzed by H5PV2Mo10O40 by an electron transfer and oxygen transfer reaction mechanism
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Primary alcohols such as 1-butanol were oxidized by the H5PV2Mo10O40 polyoxometalate in an atypical manner. Instead of C-H bond activation leading to the formation of butanal and butanoic acid, C-C bond cleavage took place leading to the formation of propanal and formaldehyde as initial products. The latter reacted with the excess 1-butanol present to yield butylformate and butylpropanate in additional oxidative transformations. Kinetic studies including measurement of kinetic isotope effects, labeling studies with 18O labeled H5PV2Mo10O40, and observation of a prerate determining step intermediate by 13C NMR leads to the formulation of a reaction mechanism based on electron transfer from the substrate to the polyoxometalate and oxygen transfer from the reduced polyoxometalate to the organic substrate. It was also shown that vicinal diols such as 1,2-ethanediol apparently react by a similar reaction mechanism. Copyright
- Khenkin, Alexander M.,Neumann, Ronny
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supporting information; scheme or table
p. 14474 - 14476
(2009/02/08)
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- Corona-induced photoxidation of alcohols and hydrocarbons over TiO 2 in the absence of a UV light source - A novel and environmentally friendly method for oxidation
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Corona-induced photooxidation is a novel oxidation methodology for the efficient oxidation of alcohols and hydrocarbons utilizing the advantage of both the high oxidizing power of ozone formed in the reactor as well as the photooxidation capability of the UV light generated during the corona discharge. The Royal Society of Chemistry 2005.
- Pillai, Unnikrishnan R.,Sahle-Demessie, Endalkachew
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p. 2256 - 2258
(2007/10/03)
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- Preparation of levulinic acid esters and formic acid esters from biomass and olefins; compositons prepared thereby; and uses of the compositions as fuel additives
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This invention relates to a process for producing a mixture of levulinic acid esters and formic acid esters from biomass and olefins, and the composition prepared therefrom. This invention also relates to usage of the mixture of these esters as fuel and as fuel additives for gasoline fuel, diesel fuel, and biofuel.
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- Novel photolactonisation from xanthenoic esters
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In the context of our work on photocleavable fragrance precursors, we have discovered a new photo-fragmentation of xanthenoic esters into xanthene- and formyl radicals. This homolytic cleavage has not been reported previously. Thus, unsaturated formyl radicals cyclise to lactones of various ring size.
- Plessis, Caroline,Derrer, Sam
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p. 6519 - 6522
(2007/10/03)
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- 'Oxenoid' oxygen insertion vs. a radical mechanism in the oxidation of alkanes and alcohols: The case of aromatic peracids
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Adamantane is oxidised by MCPBA in a free-radical process, whose selectivity is discussed; by this method, cyclohexanol can be directly oxidised to caprolactone.
- Bravo, Anna,Fontana, Francesca,Minisci, Francesco,Serri, Anna
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p. 1843 - 1844
(2007/10/03)
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- Radical versus "oxenoid" oxygen insertion mechanism in the oxidation of alkanes and alcohols by aromatic peracids. New synthetic developments
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Evidences concerning a novel free-radical mechanism for the oxidation of alkanes by aromatic peracids are reported. The mechanism involves hydrogen abstraction from the OH group of peracids by an aroyloxyl radical; the acylperoxyl radical thus generated is responsible for the selective oxidation. The reaction is affected by the presence of oxygen and it is inhibited by TEMPO and by solvents forming hydrogen bonds with peracids. A more simple and effective synthetic procedure has been developed, on the basis of the autoxidation of aliphatic and aromatic aldehydes in the presence of alkanes. It is also shown that the previously reported inertness of alcohols toward peracids must be ascribed to solvent effects, due to the formation of hydrogen bonds; in suitable solvents alcohol oxidation smoothly occurs.
- Bravo, Anna,Bjorsvik, Hans-Rene,Fontana, Francesca,Minisci, Francesco,Serri, Anna
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p. 9409 - 9416
(2007/10/03)
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- Convenient one-pot method for formylation of amines and alcohols using formic acid and 1,1'-oxalyldiimidazole
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1,1'-Oxalyldiimidazole (7) reacts with formic acid (8) in acetonitrile at room temperature to give N-formylimidazole (5), which promptly undergoes aminolysis and alcoholysis to yield formamides (2) or formates (4).
- Kitagawa,Arita,Nagahata
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p. 1655 - 1657
(2007/10/02)
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- Enol Formates: Ruthenium Catalysed Formation and Formylating Reagents
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The one-step synthesis of the enol formates, isopropenyl, hex-1-en-2-yl, and α-methylenebenzyl formates, directly from terminal alkynes and formic acid with arene-ruthenium(II) catalysts is reported.They have been shown to be effective formylating reagents, under mild and neutral conditions, to produce formamides from primary and secondary amines, formylamino esters, and in the presence of a catalytic amount of imidazole, formates from alcohols or phenols.
- Neveux, Muriel,Bruneau, Christian,Dixneuf, Pierre H.
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p. 1197 - 1199
(2007/10/02)
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- The preparation of esters of formic acid using boron oxide
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Boron oxide has been found to act as an efficient reagent in the preparation of a number of formate esters by the direct esterification of formic acid with the alcohol.The reaction is most appropriate for primary and secondery alcohols, including unsaturated alcohols.The formate ester so produced is free of contamination by unreacted alcohol.
- Carlson, Charles G.,Hall, Judith E.,Huang, Yan Y.,Kotila, Sirpa,Rauk, Arvi,Tavares, Donald F.
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p. 2461 - 2463
(2007/10/02)
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- One-Pot Conversion of Primary Alkyl Chlorides and Dichlorides into Alcohols, Diols, and Ethers via Formic Ester Intermediates under Phase-Transfer Conditions
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A procedure for the synthesis of alkyl formates, 1,ω-alkanediyl diformates, and unsaturated analogs from alkyl (or 2-alkenyl) halides and sodium formate under solid/liquid phase-transfer conditions is reported.For conversion into alcohols or diols, respectively, the formic esters can be directly hydrolyzed in the reaction mixture of their preparation.Using a related procedure, cyclic ethers are prepared from 1,ω-dichloroalkanes, sodium formate, and potassium hydroxide under solid/liquid phase-transfer conditions.
- Zahalka, Hayder A.,Sasson, Yoel
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p. 763 - 765
(2007/10/02)
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- JOINT HOMOLYTIC LIQUID-PHASE TRANSFORMATIONS OF ALKYL ORTHOFORMATES AND ACETALS
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The reaction kinetics and the reactivity of ethyl orthoformate were studied in joint transformations with 1,3-dioxane, 1,1-dialkoxyalkanes, and hexyl orthoformate, initiated by tert-butyl peroxide.It was established that the corresponding dialkyl carbonates and esters are formed as a result of specific radical-chain transformations.From the ratio of the products in the range 120-150 deg C it was determined that alkyl orthoformates are more reactive than linear and cyclic acetals.
- Kostyukevich, L. L.,Kalashnikov, S. M.,Pastushenko, E. V.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 1664 - 1666
(2007/10/02)
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- FREE-RADICAL TRANSFORMATIONS OF ALKYL ORTHOFORMATES IN THE LIQUID PHASE
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The homolytic liquid-phase reactions of trialkoxymethanes, initiated by tert-butoxyl radicals, in the range 120-150 deg C were investigated.A mechanism of an unbranched chain process was established for the fragmentation of the trialkoxymethanes with quadratic determination at the alkyl radicals; as a result the corresponding dialkyl carbonates, alkyl formates, alkanes, and carbonyl compounds are obtained.The relative rate constants (k3/k4) of the chain propagation and termination reactions and the kinetic parameteres of the transformations of the ortho esterswere calculated.The differences in the activation energies for cleavage of the C-H bonds adjacent to one and three oxygen atoms was determined (ΔE = 5.0-6.0 kcal/mole).The trialkoxymethanes are close in reactivity to 1,3-dioxanes, are inferior to 1,3-dioxolanes, and superior to dialkoxymethanes.
- Kostyukevich, L. L.,Kalashnikov, S. M.,Pastushenko, E. V.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 1659 - 1663
(2007/10/02)
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- FREE-RADICAL TRANSFORMATIONS OF TRIALKOXYMETHANES IN POLYHALOGENOALKANE MEDIA
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The free-radical transformations of trialkoxymethanes in chloroform, bromoform, and carbon tetrachloride lead to the formation of the corresponding dialkyl carbonates, alkyl formates, alkanes, alkanals, halogenoalkanes, and α-halogeno ortho esters.A mechanism for the transformations is proposed, and the reactivity of the various C-H bonds in the trialkoxymethane molecules is evaluated; the bond adjacent to the three oxygen atoms is most active.
- Rol'nik, L. Z.,Kalashnikov, S. M.,Pastushenko, E. V.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 2246 - 2249
(2007/10/02)
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